MANUAL CONTROL HEATING, VENTILATION AND AIR CONDITIONING SYSTEM 7B – 19
DAEWOO V–121 BL4
MAINTENANCE AND REPAIR
ON–VEHICLE SERVICE
GENERAL A/C SYSTEM SERVICE PROCEDURES
O–RING REPLACEMENT
Important : Even though O–rings may look identical, it is
extremely important that only recommended service re-
placement air conditioning O–rings be used or excessive
leakage of refrigerant may occur.
Important : Always slip the O–ring onto the flange tube to
ensure proper locating and sealing.
Install new Daewoo–approved service replacement air
conditioning (A/C) O–rings whenever a joint or a fitting is
disassembled, except when the O–rings are provided on
new components.
When replacing O–rings on an A/C component or a joint
connection, the fitting design should be identified to en-
sure installation of the correct air conditioning service re-
placement O–ring. Some joint connections and compo-
nents will implement a ”captured” O–ring design fitting that
uses a groove to retain the O–ring. Others do not have a
groove and use a ”non–captured” or ”standard” O–ring.
Assembly and tightening procedures are the same for
both designs, but the O–rings are different.
Notice : Before installation, verify that both O–rings and
fittings have not been nicked or deformed. Deformed or
nicked parts must be replaced. Failure to use the proper
service replacement parts and procedures may result in
excessive refrigerant leakage.
HANDLING REFRIGERANT
CAUTION : Always work in a well–ventilated area and
avoid breathing any refrigerant fumes. If you have dif-
ficulty with breathing, seek medical attention immedi-
ately. If refrigerant comes in contact with any part of
your body, flush the exposed area with water. If a rash
or pain develops, seek medical attention.
Air conditioning systems contain refrigerant. This is a
chemical mixture which requires special handling proce-
dures to avoid personal injury.
Always wear goggles and wrap a clean cloth around the
fittings, the valves and the connections when performing
work that involves opening the refrigerant system. Do not
weld or steam clean on or near any vehicle–installed air
conditioning lines or components.
All refrigerant drums are shipped with a heavy metal screw
cap. The purpose of the cap is to protect the valve and the
safety plug from damage. It is good practice to replace the
cap after each use of the drum.If it is necessary to transport or carry any container of re-
frigerant in a vehicle, do not carry it in the passenger
compartment.
HANDLING OF REFRIGERANT LINES
AND FITTINGS
Notice : Using too low or too high torque when tightening
a fitting can result in loose joints or deformed joint parts.
Both conditions can result in refrigerant leakage.
S Keep all metal tubing lines free of dents or kinks.
Any line restrictions will cause the loss of system
capacity.
S Never bend a flexible hose line to a radius of less
than four times the diameter of the hose.
S Never allow a flexible hose line to come within 65
mm (2–1/2 inches) of the exhaust manifold.
S Inspect flexible hose lines regularly for leaks or
brittleness.
S Replace flexible hose lines with new lines if you find
signs of deterioration or leaking.
S Discharge all refrigerant of the refrigeration system
before disconnecting any fitting in the refrigeration
system.
S Proceed very cautiously regardless of the gauge
readings.
CAUTION : Keep your face and your hands away from
the fitting so that you will not be injured if there hap-
pens to be liquid refrigerant in the line.
S Open the fittings very slowly.
S If you notice pressure when you loosen a fitting,
allow the pressure to bleed off as described under
”Discharging, Adding Oil, Evacuating, and Charging
Procedures for A/C System” in this section.
S Cap or tape any refrigerant line immediately after it
is opened. This will prevent the entrance of mois-
ture and dirt, which can cause internal compressor
wear or plugged lines in the condenser, the evapo-
rator core, the expansion valve, or the compressor
inlet screens.
Important : Use two proper wrenches to connect the O–
ring fittings.
S Back up the opposing fitting to prevent distortion of
the connecting lines or the components.
S Back up both the swagged fitting on the flexible
hose connections and the coupling to which it is
attached with two wrenches to prevent turning the
fitting and damaging the ground seat.
S Keep the O–rings and the seats in perfect condi-
tion. A burr or a piece of dirt may cause a refriger-
ant leak.
7D – 6IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
AUTOMATIC TEMPERATURE CONTROLLER DOES NOT
OPERATE WHEN IGNITION IS ON
StepActionValue(s)YesNo
1Check the fuse F7.
Is fuse F7 blown?–Go to Step 2Go to Step 3
2Replace fuse F7.
Is the repair complete?–System OK–
31. Remove the controller.
2. Measure the voltage between connectors A5
and A14.
Is the voltage within the specified value?11–14 vGo to Step 4Go to Step 5
41. Check the controller for damage.
2. Replace the controller if it is damaged.
Is the repair complete?–System OK–
5Check the voltage between terminal A1 and ground.
Is this voltage as specified?0 vGo to Step 6Go to Step 7
61. Check the wiring harness between fuse F7 and
the terminal A5 for damage.
2. Replace the wiring harness if it is damaged.
Is the repair complete?–System OK–
71. Check the wiring harness between terminal
A14 and ground G203 for damage.
2. Repair the wiring harness, or ground connec-
tion as required.
Is the repair complete?–System OK–
7D – 12IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
BLOWER MOTOR DOES NOT RUN AT ALL
StepActionValue(s)YesNo
11. Turn the ignition to ON.
2. Observe the temperature indication screen of
the controller.
Does the digit go on and off?–Go to Step 2Go to Step 3
2Run a self–diagnosis circuit check.
Does the display indicate a defect code?–Go to the table
for the code
that flashes.–
3Check fuse F7 in the I/P fuse block.
Is this fuse in good condition?–Go to Step 5Go to Step 4
4Replace fuse F7.
Is the repair complete?–System OK–
5Check fuse EF3 in the engine fuse block.
Is this fuse in good condition?–Go to Step 7Go to Step 6
6Replace fuse EF3.
Is the repair complete?–System OK–
71. Turn the ignition switch to ON.
2. Measure the voltage between ground and ter-
minal 87(Violet) of the blower relay.
Is the voltage within the specified value?11–14 vGo to Step 15Go to Step 8
8Measure the voltage between ground and terminal
86 (Brown) at the blower relay.
Is the voltage within the specified value?11–14 vGo to Step 10Go to Step 9
AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 13
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
91. Turn the ignition switch to OFF.
2. Check circuit (Brown) between terminal 86 of
the blower relay to F7 in the I/P fuse block.
3. Repair any problem found in the wiring or ter-
minals at the relay socket or connector C203.
Is the repair complete?–System OK–
10Measure the voltage between ground and terminal
30 (Red) at the blower relay.
Is the voltage within the specified value?11–14 vGo to Step 12Go to Step 11
111. Turn the ignition switch to OFF.
2. Check circuit (Red) between terminal 30 of the
blower relay to EF3 in the engine fuse block.
3. Repair any problem found in the wiring or ter-
minals at the fuse block connector C105, con-
nector C202, or at the relay socket.
Is the repair complete?–System OK–
121. Turn the ignition switch to OFF.
2. Check the continuity in the wiring harness be-
tween the blower relay terminal 85 (Black) and
ground.
Does the ohmmeter show the specified value? 0 ΩGo to Step 14Go to Step 13
13Repair any problem found in terminal 85 at the relay
connector, circuit (Black), Connector C201, or
ground G201.
Is the repair complete?–System OK–
14Replace the blower relay.
Is the repair complete?–System OK–
151. Turn the ignition switch to OFF.
2. Disconnect the wiring harness at the blower
motor.
3. Turn the ignition switch to ON.
4. Measure voltage between ground and blower
connector 1 (Yellow).
Is the voltage within the specified value?11–14 vGo to Step 17Go to Step 16
161. Turn the ignition switch to OFF.
2. Check circuit (Yellow) between blower connec-
tor terminal 1 and blower relay terminal 87.
3. Repair any problem found in the wiring or a
connector terminal at the blower connector,
connector C208, or the blower relay socket.
Is the repair complete?–System OK–
17Measure the resistance between the connector ter-
minals on the blower motor.
Does the resistance match the specified value? 5 ΩGo to Step 19Go to Step 18
18Replace the blower motor.
Is the repair complete?–System OK–
19Measure the resistance of circuit (Violet) between
terminal 2 of the blower connector and terminal 30
of the Max HI relay and terminal 6 of the power tran-
sistor.
Does the resistance match the specified value? 0 ΩGo to Step 21Go to Step 20
7D – 14IAUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
20Repair the problem in circuit (Violet).
Is the repair complete?–System OK–
21Measure the resistance of circuit (Black) from termi-
nal 3 of the power transistor connector to ground.
Does the resistance match the specified value? 0 ΩGo to Step 23Go to Step 22
221. Trace circuit (Black) from terminal 3 of the
power transistor connector and terminal 87 of
the Max HI relay to ground G203.
2. Repair any problem found in the wiring, ground
G203.
Is the repair complete?–System OK–
23Replace the ATC controller.
the repair complete?–System OK–
MODE CONTROL DO NOT WORK
Refer to ”A/C Blower and Motor Controls Diagram”for the electrical schematic diagram of the circuits described in this
procedure.
Mode Controls Do Not Work
StepActionValue(s)YesNo
1Measure the voltage between terminal 4 and termi-
nal 5 of the mode motor.
Is the voltage within the specified value for motor?11–14 vGo to Step 3Go to Step 2
21. Check fuse F7?
2. Check the connector and circuit (Brown and
Black) for any wiring or terminal problems.
3. Repair any problems found.
Is the repair complete?–System OK–
31. Using the Motor Control Table, measure the
voltages at the specified terminals of the speci-
fied motor connectors.
2. Change the mode settings and observe the
voltage changes.
Are the voltages as specified?See the ”Motor
Control Table”Go to Step 4Go to Step 5
4Replace the motor that does not operate properly.
Is the repair complete?–System OK–
51. Using the Motor Control Table, measure the
voltages at the specified terminals of the speci-
fied controller connectors.
2. Change the mode settings and observe the
voltage changes.
Are the voltages as specified?See the ”Motor
Control Table”Go to Step 6Go to Step 7
61. Check the wiring harness and connectors be-
tween the controller and the motor that is not
performing properly.
2. Repair or replace the wiring harness or the de-
fective terminal.
Is the repair complete?–System OK–
7Check the connector at the controller.
Is there a defective terminal?–Go to Step 8Go to Step 9
AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 17
DAEWOO V–121 BL4
COMPRESSOR MAGNETIC CLUTCH DOES NOT ENGAGE
StepActionValue(s)YesNo
11. Remove the ATC Controller from the instru-
ment panel, keeping the wiring harness con-
nected.
2. Turn the ignition switch to ON.
3. Turn the A/C switch to ON.
4. Check the voltage between ground and termi-
nal A11 on the controller.
Is the voltage within the specified value?11–14 vGo to ”Insuffi-
cient Cooling
Diagnosis”Go to Step 2
2Replace the ATC controller.
Is the repair complete?–System OK–
AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 25
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Remove the ATC controller from the instrument
panel.
2. Disconnect the harness connectors from the
ATC controller.
3. Examine the connector terminals on the har-
ness connectors and the controller connectors
and the harness wiring.
Is there a problem with any of these connectors or
the wiring?–Go to Step 8Go to Step 9
8Repair the problem found with a connector terminal
or wiring.
Is the repair complete?–System OK–
9Check continuity in the harness between the control-
ler connectors and the AMD motor connector.
S Controller terminal A2 to motor terminal 7.
S Controller terminal A8 to motor terminal 5.
S Controller terminal B6 to motor terminal 2.
S Controller terminal B5 to motor terminal 6.
S Controller terminal B4 to motor terminal 3.
Does the continuity equal the specified value? 0 ΩGo to Step 10Go to Step 11
10Repair the continuity problem.
Is the repair complete?–System OK–
111. Reconnect the AMD motor to the ATC harness.
2. Reconnect the ATC harness connectors to the
controller.
3. Turn the ignition to ON.
4. Use backprobing for voltage measurements.
5. Measure the voltage between ground and ter-
minal B5 at the controller.
Is the voltage equal to the specified value?< 4 vGo to Step 12Go to Step 14
121. Set the temperature controller to 18°C (64°F).
2. Connect a voltmeter between ground and ter-
minal A8 at the controller. It should display
about 12 v.
3. Raise the temperature setting on the controller
to 32°C (90°F).
Does the voltage equal the specified value?Drops from
12 v to 0 vGo to Step 13Go to Step 15
131. Connect a voltmeter between ground and ter-
minal A2 at the controller. It should display
about 12 v.
2. Change the temperature setting to 18°C
(64°F).
Does the voltage equal the specified value?Drops from
12 v to 0 vGo to Step 20Go to Step 15
141. Recheck the wiring harness and the connector
terminals associated with controller terminals
B4, B5, and B6, and AMD motor terminals 2, 6,
and 3.
2. Repair any problem found.
Is the repair complete?–System OK–
15Recheck all wiring circuits between the controller
and the AMD motor.
Is there a problem in the wiring or the connectors?–Go to Step 16Go to Step 17
AUTOMATIC TEMPERATURE CONTROL HEATING, VENTILATION, AND AIR CONDITIONING SYSTEM 7D – 29
DAEWOO V–121 BL4
CODE 6 – POWER TRANSISTOR ERROR
StepActionValue(s)YesNo
11. Disconnect the ATC controller connectors A
and B.
2. Disconnect the connectors from the power
transistor.
3. Measure the resistance circuit GRY/BLK from
terminal 4 of the power transistor to terminal
B1 of the ATC controller.
Does the resistance equal the specified value? 0 WGo to Step 2Go to Step 6
2Measure the resistance in the circuit from terminal
1 of the power transistor to terminal B12 of the ATC
controller.
Does the resistance equal the specified value? 0 ΩGo to Step 3Go to Step 6
31. Reconnect the wiring harness to the ATC con-
troller and to the power transistor.
2. Turn the ignition switch to ON.
3. Measure the voltage from ground to terminal
B12 of the ATC controller.
4. Cycle the fan speed controller manually from
the lowest (speed 1) to the highest speed (8).
Do the voltages measured match approximately the
specified values within ±0.5 v?1: 4.0 v
2: 5.0 v
3: 6.0 v
4: 7.0 v
5: 8.0 v
6: 9.0 v
7: 10.0 v
8: Max Hi:Go to Step 4Go to Step 5
4Replace the ATC controller.
Is the repair complete?–System OK–